Patent GB-310677-A (GB)
Title: Improvements in and relating to telegraph printers
IPC: H04L15/34
Filed: 1928-05-21
Abstract: 310,677. Easton, L. C. May 21, 1928. Strip-controlled driving-mechanism.-In tele. graph printers of the Creed type wherein the movement of selectors under the control of a perforated paper strip determines the movement of a sliding rack which operates one or more combination valve slides controlling a compressedair system, two sets of selectors are provided. respectively under the control of perforations on the two sides of the centre holes of the strip, each selector of both sets being arranged to actuate a slide of the combination valve, whereby messages perforated according to the Cable code are reproduced. A dot is represented by a perforation on the left of the line of centre holes of the strip, and a dash by a perforation on the right, the two sets of selectors 11<a>, 11<b>, Fig. 2, being arranged in two parallel rows each comprising six selectors. The operation of the machine is effected by three cams 1-3 on a common shaft 4 which makes one complete revolution for each signal printed. The cam 1, through a bell-crank 24, controls the forward movement of the selectors and subsequently retracts them to their original position. The selectors 11<a>, 11<b> consist of flat plates arranged to be moved horizontally forward, both sets being provided near the centres of their inner edges with a wide notch 13 within which a vertical bar 14 can be moved backwardly and forwardly by the bell-crank 24, the rear ends of the feelers being connected by springs 25<a> 26<b> to the extremity of the bell-crank, so that if a perforation is disposed opposite to the pecker 19 constituting the end of a feeler the pecker moves forwardly into the perforation. Each selector is provided on its upper face with projections 15, Fig. 3, engaging a space-stop 16 consisting of a flat blade pivoted on a pin 17 and arranged to swing in a horizontal plane, there being a stop 16 in the plane of each pair of selectors. The forward movement of either selector of a pair thus moves forwardly their corresponding spacestop 16 which is normally held rearwardly by a spring 18, and the vertical rack-bar 10, which rests upon the uppermost space-stop 16 when the latter is in its rearward position, thereupon descends until retarded by a space-stop beneath it. Each selector is provided near its forward end with a pair of lugs to engage the extremity of a link which connects it to its corresponding valve slide 43, the links 21<a> co-operating with the selectors 11<a> consequently being longer than the links 21b of the selectors 11<b> and arranged alternately with them. Each selector 11<a> or 11<b> can thus rock its selecting-link forwardly until a shoulder 38<a> or 38<b> thereon engages behind the vertical rack 10, which is moved to the right by the cam 3 after it has descended by the amount determined by the signal. The selecting-links 21<a>, 21b in engagement with the rack are thus moved longitudinally and produce a corresponding movement in their valve slides. The lateral movement of the rack also puts it into engagement with a pinion 9 on a shaft 8 carrying a sprocket 6 engaging the central perforations of the strip 5 and, when the rack is raised vertically by the cam 2, the strip is fed forward, the feelers having been retracted in the meantime by the vertical bar 14 controlled by the cam 1. Subsequently the head 42 of the instrument together with the rack 10 are moved to the left into their normal position by the cam 3. The movement of the vertical rack 10 is controlled in known manner by supporting it at one end of a lever which can be pulled downwardly by a spring 31, Fig. 3, and restored by a link-system actuated by the cam 2.